Answer:
The answer is: $22
Step-by-step explanation:
In order to calculate the cost of skipping practice, we have to calculate the total sum of the deficit incurred within the period, and this includes the money that would have been earned during that hour of practice if it had been attended (opportunity cost of time), and the admission fee into the carnival. This calculation is shown below:
Opportunity cost of time = $13
cost of admission into carnival = $9
Total cost of skipping practice = opportunity cost of time + cost of admission into carnival
= 13 + 9 = $22